Trimming mechanism for sewing machines



Jan. 24, 1933. F. M CARD TRIMMING MECHANISM FOR SEWING MACHINES FiledMay 1, 1931 2 Sheets-Sheet 4 1 Qwwawtov 55% firederzc M. Um'd TRIMM INGMECHANISM FOR SEWING MACHINES Filed May 1, 1931 2 Sheets$heet 2 fiedercc 1%. Card WaltTwooi a C? j z atkozmq Patented Jan. 24, 1933 ll eatem res PATENT ori ice rnnnnnro CARD, or nninenronr, CONNECTICUT,as'sreivon' To SINGER MANU FACTUBING COMPANY, or ELIZABETH, NEW JERSEY,A CORPORATION on NEW JERSEY TRIMMING MECHANISM Application filed May 1,

This inventionirelates to improvements in sewing machine trimmermechanisms and has for its ObJQClL to improve the tr mmerbladesupporting and actuating mechanlsm disclosed in W. A. Neely, No;826,596, July at, 1906, to provide for more conveniently and accurately.effecting the trimming of the lower of super-posed plies of material inthe operation of uni ling said plies by stitching.

With the above and other objects in view, as will hereinafter appear,the invention consists in the devices, combinations, and arrangements ofparts hereinafter described 15 and claimed.

The several features of the invention and the advantages attainedthereby will be readily understood from the following description of anembodiment thereof illustrated in the accompanying drawings, in whichFig. 1 is a front elevation of the bracket-arm and a portion of thework-supporting post of a sewing machine having the improved trimmermechanism, which latter is shown partly in section. Fig. 2 is an endelevation of the trimmer mechanism, the bracket-arm and the throat-plateof the machine being shown in section. Fig. 3 is a side elevation of theedge-guide and its supporting means,

as viewed from the right in Fig. 1 and also of the keeper for yieldinglyholding the trimmer-blade carrier in its inoperative position. Fig. f isa perspective view of the edge-guide and its supporting bracket. Fig. 5is a perspective view of the trimmer knife and its carrier. Fig 6 is ahorizontal section of the free end of the machine bracketarm,substantially in the plane of the mainshaft journaled in said arm.

The sewing machine illustrated in the drawings has a frame including awork-supporting post 1, and a standard. 2 for the usual bracket-arm 3which terminates in a head l overhanging the post 1. Journaled forrotation inthe bracket-arm 3 is a main-shaft 5 carrying at one end abelt-pulley 6 opposite end a crank-disk? operatively connected bymeansof a link 8 with aneedle-bar 9. i The needle-bar 9 carries at itslower end a needle 10 and is journaled for vertical rethe United Statespatent to SEWING MACHINES 1931. Serial No. 534,274.

ciprocation in a bushing 11 suitably fixed ,in the bracket-arm head 4. sAny suitable mechanism may be employed for cooperation with the needlein the forma tion of stitches, the work being preferably advanced by afeed-dog 12 of the lower fourmotion type projected through thethroat-eplate 13 upon the worlosupporting postin a raised portion of saidthroat-plate which, also provides a knife-guiding shoulder 14 Opposed tothe feed-dog12 is a pressereroller. 15 carried by an. arm 16of a bracket17 se}, cured upon the lower end of the usual spring, depressedpresser-bar 18 movable endwise vertically in bushings, as 19, secured inthe: head t of the bracketrarm. a

The under side of the. bracket arm 3 is formed with a flat faced boss20providing a" seat for a trimmer-mechanism supporting bracket 21,detachably secured upon said boss and from which projects ahorizontally. dis posed fulcrumstud 22 pivotally supporting theshouldered hub-sleeve 23 of a vertically depending swinging frame 24.The hub sleeve 23 is held on the fulcrum-stud by the head of a screw 22threadedpinto the free! end of said fulcrum-stud. The swinging. frame 2lis groovedto provide a radially ex! tending guideway 25 in which isfitted one member 26 of atwo-part carrier-block, said member 26 beingsecured in the guideway 25 i by a screw 27 for yerticaladj ustmenttoward and fromthe pivotal axis of the frame 2%. Fixed by a screw 29 ina transverse groove in the carrier-block member 26 is a complementalcarrier-block member 30 which may be adjusted upon ,themember26 in thegeneral direction ofthe swinging movements of the. frame 24, i. e,vcrosswise of the guideway 25. The carrier-block member 30 is forked atits lower end to, provide spaced arms32j spanned by a fulcrum-pin 33pivotally sup-v porting an angular trimmer-blade holder 34:, 35. In theoperative position of the swinging frame 24;, the armsof said holder issubstantially horizontal, saidarm 34 carrying the shank36 of atrimmer-l'mife'having a depending, vertically disposed fin 3;? providedwith a" cutting edge 38 directed oppositely to the direction of feed ofthe work.

The trimmer-knife shank 36 is slotted to receive a securing screw 39 anda steadying pin 40, whereby the blade 87 may be adjusted toward and fromthe line of seam formation. The other arm 35 of the trimmer-blade holderis bent upwardly at the trimmer-blade side of the carrier-block member30 into substan- 'tial parallelism therewith and is acted upon by aspring 41 in a direction to yieldingly urgetheknife-fin 37 downwardlytoward the throat-plate to an extent limited by the head of a screw 42,passing through a slot in the upper end of the holder-arm 3 3 and threaded through the member 30 to which is ad justably secured by alock-nut'43,the' spring.

41 being coiled about the shank of said screw.

42 between the holder-arm 85 and the member 30. i r

The swinging. frame 24 is releasably latchedto a vertically dependingrock-lever l 44, fulcrumed upon the swinging-framehub 23 forfvibratorymovements'about an aXis coinciding with the axis of swinging movement ofsaidfr'ame 24. The rock-lever 44 is c0nn'ected by a link 45f'with acrank-arm 46 clamped upon a horizontally disposed rock:

. shaft 47 journaled in bearing lugs 48 atthe I rear side of the machinebracket-arm 3. Se-

cured upon the rock-shaft 47 is another,

gmCiflIlk-ELIIH 49'which is forked'to straddle an f eccentric 50 uponthe main-shaft 5. The rocklever 44 terminates at its lower end in asegmentalguide-bracket 51 projecting from opposite sides of said rocklever in an are having gs the'fulcrum-axis of said rock-lever as itscenter of curvature, said guide-bracket 51 being preferablyslidablyengaged by the adjacent face of the swinging frame 24.

Yieldingly projected from the swinging aplframe 24, by a spring 53,:is alatch-bar 54 slidingly disposed in a socket 55' in the frame 24,saidlatch-bar beingedapted to enter a keeper-aperture 56 in the rock-lever44,

whereby the trimmer-frame 24 may be releasg lably locked to saidrock-lever. t

- Means is provided for conveniently retracting the latch-bar 54 fromthe keeper-aperture 56. To this end, the latch-bar has a laterallyextending pin 57 projecting through. a soshorizontally disposed slot 58in the frame 24,

said pin 57 enteringa slot 59 in a vertically directed arm'GO of arelease-lever 60, 61 fulcrumed intermediate its ends upon a pivotscrew62threaded into the frame 24. The 'desu pending otherarm 61 of therelease-lever is widenedto form a thumbspiece opposed to an adjacentfinger-piece. 63 extendingintegrally from the trimmer-frame '24. TBgrasping both'thethumb-piece 61 and the oo finger piece 63, not only maythe latch-bar 54 be readily disengaged from the rock-lever 44, but theframe 24 may be thereby convenientlyfswung forwardly beyond the latchingposition thereof for the purpose of manua allytrimming the lower plymargin in ad- Vance of the needle, preparatory to sharply turning thework as-for instance in stitchmg corners. Furthermore, the opposedthumbpiece, 61 and finger-piece 63 provide convenient means for swingingthe 'unlatch'ed frame 24 rearwardly out of operative position, thelatch-bar 54 riding theguide-bracket 51 during movement of said frameinto and out of operative position. 'When the frame 24 is thrownrearwardly out of operative position it-is held in its inoperativeposition ,by a

keeper comprising a bent spring 64 which 1 engages the elongated head ofthe screw 27, as

shown in Figs. 2 and 3 of the drawings. In the present instance, thespring 64 is secured lower presser-bar bushing 19.

It is important to properly direct theupper plyor plies of material,with whichthe lower bya screw 65 upon a collar 66 fixed upon the trimmedply or plies. are to be unitedby stitches, in order that said uppermaterial plymay not be marred by thetrimniing knife and'to insure vthatthe lower ply margin is. severed along the desired line with respectseam formation as well asfordifi'erent thicked ge-guiding fin '67disposed closely adjacent to the needle-path depends vertically from a.

shank 68, bent laterally'awayl from the line of scam formation anddetachably secured upon the forwardly extending end of an arm 69.pivotally supported by a: screw 70 upon a vertically disposed member 71of an angular bracket-71, 72. Theother member 72 of said bracket issecured bya screw 73 in 'a recessed seat provided in a supporting block74, for horizontal adjustment of said member 72 crosswise of the line ofseam forms} tion, Integral with the supporting block 74 is a splitcollar? 5 clamped by axscrew 76 for vertical and also angular adjustmentupon the lower reduced end of the needlebar bushing 11. The rearward endof the edge-guidecarrying arm 693s rounded and is providedwithspaced'notches 77 and 78 adapted to be yieldingly engaged by a V-shaped portion of a spring 79 for holding said arm in, operative andinoperative posi-' tions into which it may be swung about the .screw 70.The spring 79 is suitably fixedby screws 80, upon the bracket-'inember71.]

The present trimming mechanism. in coin-f mon with that. of the NeelyPatent No;

826.596, has the advantage of severing the work in a directionparallelwith the direc tion of feed, thereby obviating the choppy appearance ofthe trimmed edge resulting from employing an under-ply trimmer swingingin an are about a vertical axis. It

will be understood that as the pivotal axis of the trimmer-bladecarrying frame is disposed ve tically above the knife blade in itswork-severing position and is removed a considerable distance from saidknife-blade, the latter acts to sever the work in a substantiallystraight line.

The arrangement of the trimmer-blade carrying frame in slidingengagement with its actuating rock-lever and the elongated pivotbearings therefor provide a degree of rigidity conducive to accurateperformance and long wear. The adjustable yielding feature of the knifeblade provides for readily accommodating materials of differentthicknesses and the edge-guide supporting means is of a character suchas not to interfere with free handling of the work.

Having thus set forth the nature of the invention, what I claim hereinis 1. In a sewing machine having a frame including a work-support and abracket-arm overhanging the work-support, stitch-forming andwork-feeding mechanisms, a trimming mechanism comprising a verticallydisposed rock-lever having a horizontal-axis fulcrum upon saidbracketarm, means for rocking said lever, a vertically depending frameournaled coaxially with the fulcrum of and disposed adjacent to saidrock-lever for swinging movements substant ally parallel with the lineof feed, a trimmer blade carried bysaid swinging frame and having avertically disposed work-severing fin provided with a cutt ng edgeopposed to the direction of feed, and a latch releasably connecting saidswinging frame and rock-lever.

2. In a. sewing machine having a frame including a work-support and abracket-arm overhanging the work-support, stitch-forming andworlnfe'eding mechanism, a trimming mechanism comprising a verticallydisposed rock-lever having a horizontal axis fulcrum upon saidbracket-arm, means for ipcking said lever, a swinging frame journaledcoaxially with the fulcrum of and disposed adjacent to said rock-lever,a trimmerblade holder carried by said swinging frame for adjustments indirections substantially parallel with the direction offeed and radiallyof said swinging frame, a trimmer-blade carried by said swinging frameand having a vertically disposed work severing fin, and a latchreleasably connecting said swinging frame and lever.

3. In a sewing machine having a frame including a work-support and abracket-arm overhanging the work-support, stitch-forming andwork-feeding mechanisms, a trimming mechanism comprising a verticallydisposed rock-lever having a horizontal-axis fulcrumupon bmckt aria,rocking said naled coaxially with the fulcrum of, and disposed adjacentto said rock-lever, atrimmer:

blade carried by said swinging frame, a latch r-eleasably connectingsaid swlnging' frame lever, a swinging frameejour-y and rock-lever, alatch-operating lever pivotally mounted upon said swinging frame andhaving a thumb-piece, and afinger pieceextension on the swinging frameopposed to said thumb-piece. X

a. In a sewingmachinehaving a frame in-L cludinga work-support andabracket-arm overhanging the work-support, stitch-form lng'and workfeedmg mechanisms, a ,tI'lIllming mechanism comprising a supportingbracket upon the under side of said bracket, arm and carryingahorizontally disposed. fulcrum-stud, a vertically depending swings,ing-frame having a hub-sleeve pivotally mounted upon said fulcrum-pin, atrimmers blade carried by said swinging frame and having a verticallydisposed work-severiiiig fin, a. rock-lever 'f'ulcr'umed coaxially withsaid swinging frame and depending in slidable contact with said swingingframe, means for vibrating said rock-lever, a latch releasablyconnecting said swinging frame and rock-lever, and means for holdingsaid swinging frame in an inoperative position disconnected from saidrock-lever.

5. In a sewing machine having a frame including a work-support and abracket-arm overhanging the work-support, stitch-forming andwork-feeding mechanisms, a trim-' ming mechanism comprising a verticallydisposed swinging-frame having a horizontal axis journal upon saidbracketarm, means for swinging said frame, a trimmer-blade holderoverhanging the work-support and pivotally carried by said swingingframe, a trimmer-bladecarried by said holder and having a verticallydisposed work-severing fin, a spring acting upon said holder toyieldingly urge said trimmer-blade fin toward the work-support, andmeans for limitin the work-support approaching movement of thetrimmer-blade fin under the action of said sprin 6. In a sewing machinehaving a frame including a work-support and a bracket-arm overhangingthe work-support, stitch-forming and work-feeding mechanisms, a trimmingmechanism comprising a vertically dis with said holder-supportingmember, a trimmer-blade having a depending work-seversaid trimmer-blade.

7 Ina sewing machine having a vertically reciprocatory I needle and awork-feeding mechanism, the combination with a'trimmlng mechanismincluding a trimmer-blade having a depending fin provided with a cuttingedge opposed to the direction of feed for trimming the under ofsuperposed plies of'material adjacent to the outer'edge of the overlyingply,'of' means for guiding the overlying ply of material comprising anarm carrying a" depending edge-guiding fin overhangin the work-supportadjacent to the pathoi the needle, a bracket secured upon the bracketarmofthe machine and providing a pivotal support for said arm, and meansfor latching V saidarmin operative and inoperative posi- 'tionsupon saidbracket.

= In testimony whereof I have signed m name to this specification, f V

5 FREDERIG M. CARD.

